558 PHYSIOLOGY AT THE FARM. 



" 3. The cow received on the fourth day 1 4 Ib. of hay, 8 Ib. 

 of beans, and 24 Ib. of potatoes. 



14 Ib. of hay contain . . . 0.218 Ib. of fat. 



8 beans . . . 0.056 



24 potatoes . . . 0.072 



In the food, . . 0.346 



The evening's milk amounted to 12.9 Ib., and contained 0.86 

 Ib. of butter ; that of the morning to 10.32 Ib., and contained 

 0.50 Ib. of butter. The cow therefore furnished during the 

 day 1 .36 Ib. of butter. The fat in the food only amounted to 

 0.346 Ib., therefore 1.064 Ib. must have been obtained from 

 other sources. 



" 4. On the fifth day the cow received 14 Ib. of hay and 30 

 Ib. of potatoes. 



14 Ib. of hay contain . . . 0.218 Ib. of fat. 



30 potatoes . . . 0.090 



In the food, . . 0.308 



The milk of the evening amounted to J3.18 Ib., and contained 

 0.606 Ib. of butter ; that of the morning to 12.20 Ib., contain- 

 ing 0.597 Ib. of butter. The cow therefore furnished 1.203 Ib. 

 of butter. The fat in the food amounted only to 0.308 Ib. ; 

 hence 0.895 Ib. of butter must have been produced from other 

 sources." * 



Thus it cannot be doubted that the starch and sugar con- 

 tained in the food contribute, along with its fatty material, 

 to the production of butter. Any considerable amount of 

 exercise must diminish the proportion of butter in milk by the 

 additional consumption of oil, starch, and sugar which such 

 exercise occasions, owing to a greater activity of the respira- 



* * Transactions of the Chemical Society of London,' vol. i. See also 

 ' English Journal of Agriculture, ' vol. xiii. pp. 27, 28. 



